(a) Field of the Invention
The present invention relates to a variable valve lift apparatus of an engine.
(b) Description of the Related Art
An internal combustion engine generates power by burning a mixture of air and fuel in a combustion chamber. Intake valves are operated by a camshaft in order to intake the air, and the air is drawn into the combustion chamber while the intake valves are open. In addition, exhaust valves are operated by the camshaft, and exhaust gas is expelled from the combustion chamber while the exhaust valves are open.
Optimal opening/closing timing of the intake and exhaust valves depends on the rotation speed of the engine. Variable valve lift (VVL) apparatus have therefore been developed. These apparatus allow different valve timing depending on the engine speed.
Such a VVL apparatus should minimize power loss in driving the valves using torque of the camshaft. In addition, it should be symmetrical, so it can be installed in both banks in a V-engine.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.